1. Field of the Invention
The present invention relates to an LED (light emitting diode) package structure and a manufacturing process thereof, and more particularly, to an LED package structure and a manufacturing process thereof adapted for alternate current light emitting diodes (AC LEDs).
2. Description of Related Art
Referring to FIG. 1, an exploded view illustrating a conventional LED package structure, to FIG. 2, a cross-sectional view illustrating the conventional LED package structure, and to FIG. 3, a perspective view illustrating the conventional LED package structure formed with an insulating outer frame, in the conventional LED package structure, positive and negative electrode lead frames come from an integral material sheet 13, namely, a known integral material sheet 13 includes a rectangular side frame 131, a pair of electrode lead frames 132a,132b, and a pair of supports 133a,133b. The two electrode lead frames 132a,132b extend, respectively, from two parallel internal sides of the rectangular side frame 131, whereas the two supports 133a,133b extend, respectively, from other two parallel internal sides of the rectangular side frame 131. Both the two supports 133a,133b are connected with a positioning collar 134, while the two electrode lead frames 132a,132b are spaced apart from the positioning collar 134.
In manufacturing the conventional LED package structure, a circular heat-sink block 10 (including a base position 11, and a rise portion 12 protruded from the base position 11) is positioned in the integral material sheet 13. Then, in cooperation with molding, an insulating outer frame 14 is formed eventually by injection of an insulating plastic material, as shown in FIG. 2. The gap between the electrode lead frames 132a,132b and the positioning collar 134, between the positioning collar 134 and the rise portion 12 horizontally, between the electrode lead frames 132a,132b and the base position 11, and between the positioning collar 134 and the base position 11 vertically, are filled with the insulating plastic material in the same step of process. The base position 11 of the heat-sink block 10 will be exposed, in part (so-called “exposing area 111”), out of the insulating outer frame 14. Thereafter, a further step in removing the supports 133a,133b is necessary, because the supports 133a,133b, though useless for a final product of LED, are required for fixing the heat-sink block 10 during the manufacturing process.
However, there are several disadvantages for the conventional LED package structure in respect of electrical insulation, particularly in the occasion of using alternate current, namely:
Firstly, a supporting mechanism is necessary in order to maintain a particular vertical gap between the electrode lead frames 132a,132b and the heat-sink block 10 such that the subsequent injection molding material can be filled therein, for instance, a mold-auxiliary measure can be adopted. In case the supporting mechanism is unsatisfactory, the electrode lead frames 132a,132b may possibly oblique and fail to be parallel completely with a top surface of the base position 11 of the heat-sink block 10. As a result, a vertical spacing H1 between the electrode lead frames 132a,132b and the heat-sink block 10 cannot be maintained at a predetermined safety value everywhere therebetween.
Secondly, after injection of the insulating plastic material, the gaps supposed to be filled completely may on the other hand not be filled completely, and this may bring forth a risk that an electric ark might penetrate into the heat-sink block 10.
Thirdly, even though the supports 133a,133b are eventually cut off, metal burrs 15 are often left thereon, and this would result in an electric arc discharge route which is destructive to electric voltage resistance.
Fourthly, in the conventional LED package structure, the exposing area 111 of the heat-sink block 10 and the electrode lead frame area, which is not enveloped by the insulating outer frame 14, are apart from each other at a horizontal distance D1 mostly less than 2 mm. This will often results in an electric arc conduction.
It has been a main trend for electric components to meet safety requirements for voltage resistance. To avoid electric shock caused by short circuit at insulation portions, such that safety requirements for CE and UL must reach to a voltage resistance of (1000+2U)V where “U” refers to a “working voltage,” a solution to solve the problems becomes a demand.